Particulate matter, or PM, is not just one contaminant or pollutant.
It’s a range of particles of dust, dirt, and liquids that become suspended in the air. Some of these are large enough to see, like smoke, smog, or soot, but the most harmful are smaller, invisible particles. These can get into your lungs and even your bloodstream. The healthier the air, the fewer PMs.
What's the difference between the types of PM?
PM is categorised depending on the size of the particle.
As particulate matter is so vast, scientists found a way to measure it. PM1 for example, refers to the size of the particle.
- PM1 are extremely fine particulates with a diameter of fewer than 1 microns.
- PM2.5 (also known as fine particles) have a diameter of less than 2.5 microns.
- PM10 means the particles have a diameter less than 10 microns, or 100 times smaller than a millimeter.
PM10 includes PM10 sized particles and everything smaller in size.